The conservative oil billionaires Charles and David Koch are spending millions on television ads meant to turn the failure of the Solyndra solar energy company into an election liability for Barack Obama.

The group Americans for Prosperity, which is funded by the Kochs, said on Wednesday it was spending $2.4m on television ads accusing Obama of putting billions of taxpayer dollars at risk to help political donors.

"The American people have absolutely had enough. They are sick of being put on the hook for expensive and wasteful loans to President Obama's so-called green energy pet projects," said Tim Phillips, a longtime lobbyist who now heads Americans for Prosperity.

The same group helped organise the Tea Party protests against Obama in 2009. It has said the ads will run for two weeks on stations in Florida, Michigan, Virginia, and New Mexico. All are battleground states in the 2012 presidential election.

As far as political spending goes, $2.4m is relatively modest for the Kochs. Their network of oil refineries and ownership of consumer brands such as Lycra has made them among the richest men in America.

In the last few years the brothers have spent more than $50m to advance their political agenda, supporting foundations such as Americans for Prosperity, which opposes pollution controls and has worked to discredit the science on climate change.

The Kochs spent nearly $7m to fund Americans for Prosperity in 2007, according to tax records. The group reported income of $22m last year, from anonymous donors.

The Kochs are reportedly gearing up to spend another $200m in the 2012 elections.

But the ad buy on Solyndra, the solar panel company which went bankrupt after receiving $535m in federal government loan guarantees, is the biggest foray into the 2012 elections to date for Americans for Prosperity. The amount already exceeds the $1.3m the group spent on ads in the 2010 elections. Americans for Prosperity said this should be seen as an indicator of its strategy for 2012.

The ad opens with shots of a fake newspaper front page, called the Solyndra News, while a voiceover accuses Obama of giving favours to wealthy donors. It goes on to question the entire clean-energy loan programme at the department of energy – a programme that was in fact put in place under George Bush.

"Risking billions of taxpayer dollars to help his political donors. Is this the change we are supposed to believe in?" the voiceover asks.

The White House has rejected charges, led by Republicans, that politics influenced decisions on the loan guarantee for Solyndra.